Thursday, Sept. 15th, 2011 - 11.00 a.m.
Building E - Room 1

Leonardo Banchi - University of Firenze, Dept. of Physics

Transmission of quantum states and entanglement between distant quantum processors is an important task in the design of a quantum computing architecture.  I will show that effective quantum-state and entanglement transfer can be obtained by inducing a ballistic dispersionless dynamics in quantum wires with (almost) homogeneous intra-wire interactions. When the wire consists of a spin-1/2 XX chain, our procedure ensures a high-quality entanglement transfer even in the limit of arbitrarily long channels, almost independently of the channel initialization.  For instance, the average quantum state transmission fidelity exceeds 90% for any chain length. Moreover, the dispersionless dynamics can be used for achieving an effective quantum gate between distant qubits, by exploiting the phases acquired by the various states during the transmission. The results are then generalized to others spin-1/2 models where more complicated effects take place. Finally, an experimental proposal using cold atoms systems is considered for testing our predictions.